If the ECU detects an abnormal signal from a sensor while the vehicle is being driven, the ECU illuminates the engine trouble warning light and provides the engine with alternate operating instructions that are appropriate for the type of malfunction.
When an abnormal signal is received from a sensor, the ECU processes the specified values that are programmed for each sensor in order to provide the engine with alternate operating instructions that enable the engine to continue to operate or stop operating, depending on the conditions.
Self-Diagnostic Function table

Ecu self-diagnostic function
Troubleshooting methodChecking the lean angle sensor
1. Remove:
Lean angle sensor
2. Check:
Lean angle sensor output voltage
Out of specification Replace.
a. Connect the lean angle sensor to the wire
harness.
b. Connect the pocket tester (DC 20 V) to the
lean angle sensor coupler as shown.
Positive tester probe
yellow/green "1"
Neg ...
Checking the throttle body joint and air filter case joint
1. Remove:
Right lower side cowling
Left lower side cowling
Refer to "GENERAL CHASSIS" on page 4-1.
2. Check:
Throttle body joint "1"
Air filter case joint "2"
Cracks/damage Replace.
3. Install:
Right lower side cowling
Left lower side cowling
Refer to "GENERAL CHAS ...
Removing the handlebars
1. Stand the vehicle on a level surface.
WARNINGSecurely support the vehicle so that there
is
no danger of it falling over.
2. Remove:
Handlebar grip "1"
NOTE:
Blow compressed air between the handlebar
and the handlebar grip, and gradually push the
grip off the handleb ...